Illuminating apparatus and device manufacturing method

ABSTRACT

A laser beam from an excimer laser is split into three beams along a first plane by a pair of prisms and the three beams are caused to intersect each other at the position of the object side focal point of a first cylindrical lens and be incident upon the first cylindrical lens. The three beams are respectively focused independently from each other by the first cylindrical lens. The above focused three beams are then focused along a second plane perpendicular to the first plane by a second cylindrical lens; then, the three beams are caused to superimpose each other on a mask and at the same time are brought to a defocus along the first plane and into focus again along the second plane by an anamorphic optical system containing a third cylindrical lens and a lens having a rotation symmetry, thereby a line-like illumination area extended in the first direction is formed on the mask. The linear illumination area and an area containing a pattern of a series of openings arranged in the first direction or a rectangular pattern extended in the first direction are caused to coincide on the mask to efficiently illuminate the pattern. An image of the illuminated pattern is projected onto a workpiece for an orifice plate by a projection lens system to process the workpiece in accordance with the pattern.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to illuminating apparatus and devicemanufacturing methods and, more particularly relates to an illuminatingapparatus and a device manufacturing method suitable in processing anozzle hole or a groove of an ink reservoir of an orifice plate for anink-jet printer.

2. Description of the Related Art

Recently, it is increasingly common to fabricate a precision part by amask projection method. Lasers are used as the light source and apattern on a mask illuminated by a laser beam is projected by aprojection lens onto a surface to be processed so that the precisionprocessing is effected by an optical energy of the laser beam which haspassed through the pattern. This method is particularly excellent in itshigh productivity and in that the processing may be effected stably at ahigh precision.

One of the types of part processing suitably using the mask projectionmethod is the processing of an orifice plate for an ink-jet printer or abubble jet printer (hereinafter referred to as an ink-jet printer). Ingeneral, an ink-jet printer refers to the type of printer in whichcharacters or graphics are printed by intermittently ejecting ink onto asurface of a sheet from a large number of small holes having a diameterof 20 to 50 μm which are arranged in a row. An orifice plate refers to amember having the large number of small holes (nozzles) for ejecting theink. In order to improve the quality of characters to be printed, it isimportant, in addition to an accurate control of timing of the inkejection, that the large number of small holes on the orifice plate beprovided at a high precision. Further, in order to lower the cost perunit of the orifice plate, i.e., the cost per unit of printer, it isnecessary to improve the productivity in mass production of the orificeplate. If the orifice plate is manufactured by using the mask projectionmethod, it is important to efficiently illuminate the pattern of a mask.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an illuminatingapparatus and a device manufacturing method in which a linear area maybe efficiently illuminated.

An illuminating apparatus according to the present invention includes: afirst anamorphic optical system for focusing an illuminating beam withrespect to a first direction; a second anamorphic optical system forfocusing said focused illuminating beam with respect to a seconddirection substantially perpendicular to said first direction; and athird optical system for bringing the illuminating beam focused withrespect to said two directions into focus again with respect to saidsecond direction and at the same time into a defocus with respect tosaid first direction to form a linear illumination area extended in saidfirst direction on an illuminated surface.

Further, a device manufacturing method according to the presentinvention includes the steps of: forming said linear illumination areaof said illuminating apparatus on a mask; and exposing a workpiecethrough a pattern within said linear illumination area on said mask.

In an embodiment of the present invention to be described later, saidilluminating apparatus includes a beam splitter having a pair of prismsfor forming a plurality of beams serving as said illuminating beam bysplitting the light from a light source, and the third optical system isso constructed as to cause said plurality of beams to superimpose eachother on said illuminated surface and at the same time to bring each ofsaid plurality of beams into focus with respect to said second directionand to a defocus with respect to said first direction on saidilluminated surface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view schematically showing certain portions of a firstembodiment of the present invention.

FIG. 2 is a side view schematically showing certain portions of thefirst embodiment of the present invention.

FIG. 3(A) and 3(B) show in detail the portion from y-direction beamsplitting means 4 to second cylindrical lens 7.

FIG. 4(A) is a front view of a mask and

FIG. 4(B) is an enlarged portion of that view.

FIG. 5 illustrates the illumination range of a mask pattern.

FIG. 6 shows a nozzle and groove of an ink reservoir.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a plan view schematically showing certain portions of a firstembodiment of the present invention; and FIG. 2 is a side view ofcertain portions of the first embodiment of the present invention. Forthe convenience of explanation, an optical axis of an optical system isdefined as an x-axis and x-y-z coordinates are set as having an x-yplane corresponding to the plan view and an x-z plane corresponding tothe side view. Here, the y-axis and z-axis are determined to be a firstdirection and a second direction, respectively, and the x-y plane andx-z plane are determined to be a first plane and a second plane,respectively.

In the figures, what is denoted by numeral 1 is a light source for whicha laser such as a KrF excimer laser is used. Numerals 2 and 3 arebending mirrors, respectively, and an a y-direction beam splitting means4 splits the laser beam into a plurality of beams that are different indirection from each other within the x-y plane. Denoted by numeral 5 isa shield mask and 6 is a first cylindrical lens (first anamorphicoptical system) which has a light converging effect only in they-direction. Denoted by SL2 is a cylindrical lens unit consisting of asecond cylindrical lens (second anamorphic optical system) 7 having alight converging effect only in the z-direction and a third cylindricallens (cylindrical lens unit) 8 having a light converging effect only inthe z-direction. Denoted by numeral 9 is an ordinary convex lens(condenser) shaped in a rotation symmetry having a light convergingeffect in both the y- and z-directions. Numeral 10 is a mask which isdisposed on a surface to be illuminated.

The position of the mask 10 and the image focal point F₉ ' of the convexlens 9 coincide. Numeral 12 is a projection lens and 11 is an entrancepupil of the projection lens 12 (in some cases, an aperture stop servingas the entrance pupil). Numeral 13 is a workpiece which, in the case ofthe present embodiment, is a plate consisting of a plastic material tobe processed into the orifice plate of an ink-jet printer. Theprojection lens 12 projects an image of a pattern on the mask 10(referred to as a mask pattern or projection pattern) onto a surface ofthe workpiece 13. The orifice plate has an array of nozzle holes 61 asshown in FIG. 6. Further, an ink groove 62 for keeping ink is providedcorresponding to each nozzle hole. Accordingly, a pattern arrangingsmall circular openings in a row or a pattern of a slender rectangularopening is provided on the mask 10 so as to be used in the processing ofan array of nozzle holes 61 and/or an ink groove 62.

FIGS. 3(A) and 3(B) show in detail the portion of the y-direction beamsplitting means 4, shield mask 5, first cylindrical lens 6 and secondcylindrical lens 7. FIG. 3A is a plan view and FIG. 3B is a side view.

FIG. 4(A) is a front view of the mask 10 of the present embodiment. Thepattern of the mask 10 is in the form of regularly disposing transparentsmall holes having a diameter L_(z0) (FIG. 4(B)) along a straight linein the y-direction on an opaque background portion, the total length inthe y-direction being L_(y0) and the width in the z-direction beingL_(z0). The mask 10 is obtained such that a metal film (backgroundportion) such as a chrome film is formed on a transparent substrate anda pattern (array of small holes) is formed by a patterning.

In the present embodiment, the pattern of the mask 10 is projected ontothe workpiece (plate member) 13 to form a large number of small holeshaving a diameter of 20 to 50 μm within a length of about 10 mm on theworkpiece.

Supposing the projecting magnification of the projection lens 12 as 1/5,the size of the mask pattern is a pattern where transparent small holeshaving a diameter of L_(z0) =0.1˜0.25 mm are arranged in a distance ofL_(y0) =50 mm.

The direction of the length of the mask pattern (y-direction), the beamsplitting direction of the y-direction beam splitting means 4, thedirection of generating lines of the second cylindrical lens 7 and thirdcylindrical lens 8 all coincide, and the mask 10 is disposed so that thecenter of the mask pattern and the x-axis coincide.

The operation of the present embodiment will now be described. Theoptical operation of the present embodiment will be described in twosteps, since the operation in the x-y plane and the operation in the x-zplane are different from each other.

The operation in the x-y plane (first plane) will be first described byway of FIGS. 1 and 3(A). A substantially collimated laser beam emittedin the direction of an optical axis from the light source 1 is a beamhaving a cross section of which the width in the y-direction is largerthan the width in the z-direction. This beam is reflected at the mirrors2, 3 and is then incident upon the y-direction beam splitting means 4.As shown in FIG. 3(A), the y-direction beam splitting means 4 has twoprisms 4a, 4b arranged in the y-direction with a separation from eachother and splits the incident beam into three beams that are differentin travelling direction from each other within the x-y plane. Thesebeams are not converged nor diverged in the z-direction by the splittingmeans 4.

The respective central rays (principal rays) of the three split beamsintersect at a point F_(6y) on the optical axis, and the shield mask 5having an opening at the center thereof is disposed at the positionF_(6y). The shield mask 5 equalizes the y-direction width of the threesplit beams to each other and at the same time eliminates stray lightoccurring prior to the y-direction beam splitting means 4.

The shield mask 5 is disposed at the position of an object focal pointF_(6y) (the subscript letters _(y),z indicating the elements of they-direction and z-direction, respectively) of the first cylindrical lens6, thereby the center ray of each beam emitted from the firstcylindrical lens 6 becomes parallel to the optical axis. That is, themask 5 and lens 6 constitute a so-called telecentric optical system.Thus, three images (intermediate images in the x-y plane) I_(6y+),I_(6y0), I_(6y-) are formed at the focal point position F_(6y) ' on theimage side of the first cylindrical lens 6. In this image formationwithin the plane, the second cylindrical lens 7 acts simply as aparallel flat plate. It should be noted that these images within the x-zplane are straight line-like images parallel to the z-axis, since eachbeam is spread in a direction parallel to the z-axis.

Next, the third cylindrical lens 8 also acts simply as a parallel flatplate, and the convex lens 9 forms the above line image I_(6y+),I_(6y0), I_(6y-) into an image I_(9y-), I_(9y0), I_(9y+) on the entrancepupil plane 11 of the projection lens 12. Here, since the position ofthe mask 10 is the image side focal point of the convex lens 9, all thethree beams thereat superimpose each other within the x-y plane at thesame time of being defocused. The length of this overlapped portion isdefined as L_(y). The extent L_(y) is so designed as to sufficientlycover an extent L_(Y0) in the y-direction of the mask pattern as shownin FIG. 5.

The projection lens 12 forms an image of the pattern of the mask 10illuminated by the three beams on the workpiece 13.

As described, according to the present embodiment, the beam from thelaser 1 within the x-y plane is split into three beams and they arerespectively formed into an image as a linear light source I_(6y+),I_(6y0), I_(6y-), and its image I_(9y-), I_(9y0), I_(9y+) is formedagain within the entrance pupil 11 of the projection lens 12 to achievea Kohler illumination on the mask 10 and workpiece 13. The mask 10 andworkpiece 13 are thus illuminated by a light having a uniformilluminance with respect to the y-direction.

It should be noted that the focal distance f_(6y) of the firstcylindrical lens 6 is determined based on the diameter (width) a_(6y) inthe y-direction of the beam incident upon the first cylindrical lens 6,the focal distance f_(9y) of the convex lens 9 and the length L_(y) ofthe illuminated area on the mask 10. That is, supposing m_(9y) as animage forming magnification by which the convex lens 9 forms an image ofthe light source image I_(6y+), I_(6y0), I_(6y-) having been formed bythe first cylindrical lens 6 on the entrance pupil (aperture of stop)11, and b_(9y) as the distance from the image side principal plane ofthe convex lens 9 to the entrance pupil 11 of the projection lens 12,the focal distance f_(6y) of the first cylindrical lens 6 is obtainedas:

    f.sub.6y =a.sub.6y *{(b.sub.9y -f.sub.9)/L.sub.y }* |1/m.sub.9y |                                                (1)

where "*" indicates a multiplication.

It is desirable that the illumination area L_(y) of the mask 10 hasabout the same as or is increased by as much as 20% from the lengthL_(y0) in the y-direction of the pattern of the mask, i.e.:

    L.sub.y0 ≦L.sub.y ≦1.2*L.sub.y0.             (2)

To achieve this, it suffices that the focal distance f_(6y) of the firstcylindrical lens 6 is determined by setting the incident width a_(6y) ofthe beam upon the first cylindrical lens 6 as a_(6y) ˜(a_(6y) /1.2),while, in effect, a beam having a width of a_(6y) is caused to beincident thereupon. In other words, the focal distance f_(6y) may bedetermined by the following equation:

    f.sub.6y =k*a.sub.6y *{(b.sub.9y -f.sub.9)/L.sub.y0 }*|1/m.sub.9y |                                                (3)

where k=1˜1/1.2 and "*" indicates a multiplication.

Next, based on this result, the apex angle (wedge angle) of the twoprisms 4a, 4b that constitute the y-direction beam splitting means 4 iscalculated. The emitting angle for the y-direction beam splitting means4 is determined by the focal distance f_(6y) of the first cylindricallens 6, the diameter A₁₁ of the entrance pupil 11 of the projection lens12, and the image forming magnification m_(9y) in the y-direction of theconvex lens 9.

That is, in order that an image of the above three light sources I₆₊,I₆₀, I₆₋ be formed within the entrance pupil 11, the followingconditions of:

    tan (q.sub.6y-max)≦(A.sub.11 /2)/(f.sub.6y *m.sub.9y) (4)

must be met, where θ_(6y-max) is an angle between the optical axis andthe beam emitted from the y-direction beam splitting means 4 (see FIGS.3(A) and 3(B)) and "*" indicates a multiplication.

The two prisms 4a, 4b may be constituted by prisms having an angle ofdeviation of θ_(6y-max) as obtained by equation (4).

It should be noted that, in determining their optical disposition, theoptical effects of the second cylindrical lens 7 and third cylindricallens 8 must be considered.

The optical operation of the present embodiment within the x-y plane isas described above.

The operation within the x-z plane (second plane) will now be describedby way of FIGS. 2 and 3(B).

In this plane, the y-direction beam splitting means 4 and the firstcylindrical lens 6 act only as a parallel flat plate with respect to theincident beam. The incident beam is subjected to a converging effectrespectively at the second cylindrical lens 7 and third cylindrical lens8. Within this plane, the beam from the light source 1 is incident uponthe second cylindrical lens 7 as a beam consisting of a bundle of raysthat are substantially parallel to each other. A light source image(intermediate image within the x-z plane) I_(7z) is then formed at afocal point position F_(7z) ' (second converging point) of the secondcylindrical lens 7. Since this light source image is spread into threebeams in the y-direction, it is formed as three linear images I_(7z+),I_(7z0) , I_(7z-) (see FIG. 1).

Next, these images are subjected to a converging effect by the thirdcylindrical lens 8 and is furthermore subjected to a converging effectby the convex lens 9 to be focused again at the position of the mask 10.

That is, the three line images I_(7z+), I_(7z0), I_(7z-) are formed intoan image again at the position of the mask 10 as one line image I_(9z)by the third cylindrical lens 8 and convex lens 9. The image formingmagnification at this time is m₈˜9,z.

The projection lens 12 forms an image of the pattern of the mask 10illuminated by a beam having a size close to a point in the z-directionon the workpiece 13.

It should be noted that, supposing w as a divergence angle of the laserand f_(7z) as the focal distance of the second cylindrical lens 7, thesize in the z-direction s_(7z) of the image I_(7z) formed by the secondcylindrical lens 7 is obtained as:

    S.sub.7z =w*f.sub.7z                                       (5)

and the size in the z-direction L_(z) of the image I_(9z) formed on themask 10 is obtained as:

    L.sub.z =S.sub.7z *m.sub.8˜9,z

    L.sub.z =w*f.sub.7z *m.sub.8˜9,z                     (6)

According to the experiments, a suitable range of the size L_(z) is:

    3*L.sub.z0 ≦L.sub.z ≦30*L.sub.z0             (7)

where "*" indicates a multiplication.

That is, with respect to the z-direction, the focal distance f_(7z) ofthe second cylindrical lens 7 and the image forming magnification m₈˜9,zof the second cylindrical lens 8 and convex lens 9 satisfying equation(6) are determined from the laser divergence angle w and a desireddimension L_(z), and, then, the focal distance f_(8z) of the secondcylindrical lens 8 and the position thereof may be determined.

Thereby, the width of a line-like illumination area may now be varied ata greater degree of freedom by suitably arranging the two cylindricallenses, i.e., the second and third cylindrical lenses.

It is however preferable that the focal distances f_(7z), f_(8z) of thesecond cylindrical lens 7 and third cylindrical lens 8 and the positionsof the two satisfy the following conditions.

I. The distance from the first cylindrical lens 6 to the convex lens 9is already determined from the relation of the image formation withinthe x-y plane. Accordingly, the second cylindrical lens 7 is preferablydisposed within this distance. However, the third cylindrical lens 8 maybe disposed on either the light source 1 side or the mask 10 side fromthe convex lens 9.

II. The incident beam is preferably incident upon the entrance pupil 11of the projection lens 12 without causing a vignetting of the lens. Toachieve this, it is preferable to satisfy the following conditions.

    (d.sub.10˜11 /m.sub.8˜9,z)*(a.sub.7z /f.sub.7z)≦A.sub.11 (8)

where: a_(7z) is the width in the z-direction of the beam incident uponthe second cylindrical lens 7; d₁₀˜11 is a distance from the mask 10 tothe entrance pupil 11; and A₁₁ is a diameter of the entrance pupil.

It should be noted that, since the line-like images I_(9y-), I_(9y0),I_(9y+) are formed within the entrance pupil 11 and the shape of theseimages as a whole is rectangular, it is preferable to consider this factwhen suitably determining the size or shape of the entrance pupil 11.("*" indicates a multiplication.)

Based on the above construction, in the present embodiment, the laserbeam within the x-z plane is formed into a linear image on the mask 10as shown in FIG. 5 to achieve a critical illumination while sufficientlycovering the dimension L_(z0) in the z-direction of the pattern.Thereby, an illumination having a very high density may be achieved whena pattern is projected on the workpiece.

As described, according to the present embodiment, a Kohler illuminationfor uniformly illuminating the pattern to be projected is achievedwithin the x-y plane while sufficiently covering the length in they-direction thereof, while, in the x-z plane, a critical illumination isachieved for covering the dimension in the z-direction of the pattern tobe projected for a suitable range to form (an image in that range with)the beam from the light source into a desired image. Thereby, aprojection apparatus is achieved, which is far superior to aconventional laser processing optical system in the efficiency of energyconsumption.

The constructing procedure for the projection apparatus will now bedescribed.

First, from the processing dimension on a workpiece and the processingprecision thereof, a suitable projection lens and its projectingmagnification for processing are determined. Upon the determination ofthe projection lens, the position and diameter of its entrance pupil arealso determined. Then, the pattern of the mask is thereby determined.

Next, upon the determination of the illuminating dimensions L_(y), L_(z)on the mask, of the optical elements of the illuminating system, thebasic numerical values for the optical elements of the y-direction beamsplitting means 4, shield mask 5, first cylindrical lens 6 and convexlens 9 are determined from the equations (3), (4). By satisfying theserelations, a laser processing optical system may be achieved, which iscapable of providing a uniform illumination in the y-direction.

Next, based on equation (6), the respective focal distance anddisposition of the second cylindrical lens 7 and third cylindrical lens8 for accurately illuminating the z-direction of the mask aredetermined. Thereby, the pattern to be projected may be accuratelyilluminated also with respect to the z-direction.

The constructing procedure is as described above. It should be notedthat, while, in the present embodiment, the cylindrical lenses are eachconstructed by a single cylindrical lens, they may be respectivelyconstituted by a plurality of cylindrical lenses.

If the projection apparatus of the present embodiment is applied to themanufacturing of an orifice plate, i.e., an ink-jet printer, the orificeplate may be manufactured at a high productivity. It is thereby possibleto reduce the cost of the orifice plate, i.e., of the ink-jet printer.

If, in the above described embodiment, the light source is constructedby something other than a laser, rays of light emitted from the lightsource are brought into parallel to each other and then may be caused tobe incident upon the y-direction beam splitting means 4. Any size largerthan the effective portion of the y-direction beam splitting means 4suffices as the size of a beam to be incident upon the y-direction beamsplitting means 4. Further, if no nonuniformity occurs in the intensitydistribution of the beam in the y-direction, a system may be constructedwithout using a y-direction beam splitting means.

It should be noted that, while, in the present embodiment, no beamexpanding means or no beam reducing means is provided between the lightsource 1 and the y-direction beam splitting means 4, the disposition ofsuch means causes no problem if the beam sufficiently covers theeffective portion of the y-direction beam splitting means 4. Further, itis also possible to project a mask pattern on the workpiece 13 withoutan intermediary of a projection lens.

Based on the construction as described above, the present embodimentachieves a projection apparatus suitable for a laser processing opticalsystem which is capable of illuminating a unidimensional line-like maskpattern at a very high efficiency of energy utilization (lightutilization efficiency).

Also, an optimal projection apparatus for performing a laser processingof a line-like pattern is achieved, in which, by suitably setting therespective elements of the illumination means, the lengthwise dimensionand widthwise dimension of a line-like illumination area may be variedat a high degree of freedom and the respective changes in the first andsecond directions of the illumination area on the illuminated surfacemay be made independently while assuring a high energy density.

A projection apparatus is achieved, which is capable of laser processingat a high accuracy by a simple construction by using a beam splittingelement, for example, of a prism group, without using a fly-eye lens.

A manufacturing method of an orifice plate is achieved in which theproductivity is improved and a lower cost is achieved as a partprocessing.

A low-cost ink jet printer using a low-cost orifice is achieved.

What is claimed is:
 1. An illuminating apparatus for forming a linearillumination area on a surface to be illuminated, said apparatuscomprising:a first anamorphic optical system for bringing anillumination beam into focus with respect to a first direction; a secondanamorphic optical system for bringing the illumination beam into focuswith respect to a second direction substantially perpendicular to thefirst direction; and a third optical system for forming a linearillumination area extended in the first direction on the surface bybringing the illumination beam focused sequentially with respect to thetwo directions into focus with respect to the second direction and intodefocus with respect to the first direction on the surface.
 2. Anilluminating apparatus for forming a linear illumination area on asurface to be illuminated, said apparatus comprising:a first anamorphicoptical system for bringing an illumination beam into focus with respectto a first direction; a second anamorphic optical system for bringingthe illumination beam into focus with respect to a second directionsubstantially perpendicular to the first direction; a third opticalsystem for forming a linear illumination area extended in the firstdirection on the surface by bringing the illumination beam focusedsequentially with respect to the two directions into focus with respectto the second direction and into a defocus with respect to the firstdirection on the surface; and a beam splitter for forming a plurality ofbeams serving as the illumination beam by splitting light from a lightsource, wherein said third optical system causes the plurality of beamsto overlap each other on the illuminated surface and brings each of theplurality of beams into focus with respect to the second direction andat the same time to defocus with respect to the first direction on theilluminated surface.
 3. An apparatus according to claim 2, wherein saidbeam splitter directs the plurality of beams to different directionsfrom each other along a first plane containing the first direction andthe optical axis such that the plurality of beams intersect each otherat a point on the optical axis along the first plane.
 4. An apparatusaccording to claim 3, wherein the intersecting position and the positionof an object side focal point of the first anamorphic optical systemalong the first plane substantially coincide.
 5. An apparatus accordingto claim 4, wherein said beam splitter includes a plurality of prisms.6. An apparatus according to any one of claims 1 to 5, wherein saidfirst anamorphic optical system is constituted by a single cylindricallens.
 7. An apparatus according to any one of claims 1 to 5, whereinsaid first anamorphic optical system is constituted by a plurality ofcylindrical lenses.
 8. An apparatus according to any one of claims 1 to5, wherein said second anamorphic optical system is constituted by asingle cylindrical lens.
 9. An apparatus according to any one of claims1 to 5, wherein said second anamorphic optical system is constituted bya plurality of cylindrical lenses.
 10. An apparatus according to any oneof claims 1 to 5, wherein said third optical system is an anamorphicoptical system.
 11. An apparatus according to claim 10, wherein saidthird optical system includes a cylindrical lens having a refractingpower with respect to the first direction and a lens having the samerefracting power with respect to the first and second directions.
 12. Anexposure system having an apparatus according to one of claims 1 to 5,said exposure system forming the linear illumination area on a mask andexposing a substrate through a pattern within the linear illuminationarea on the mask.
 13. An exposure system according to claim 12, furthercomprising a projection optical system for projecting an image of thepattern of the mask onto the substrate.
 14. An exposure system accordingto claim 13, wherein the focus position of the illumination beam by saidfirst anamorphic optical system and a pupil position of said projectionoptical system occupy optically conjugate positions.
 15. A devicemanufacturing method comprising the steps of:bringing an illuminationbeam into focus with respect to a first direction by a first anamorphicoptical system; bringing the illumination beam into focus with respectto a second direction substantially perpendicular to the first directionby a second anamorphic optical system; and forming, by a third opticalsystem, a linear illumination area extended in the first direction on amask by bringing the illumination beam focused sequentially with respectto the two directions into focus with respect to the second directionand into defocus with respect to the first direction on the mask; andexposing a workpiece through a pattern within the linear illuminationarea on the mask.
 16. A method according to claim 15, wherein thepattern on the mask includes a plurality of small openings arrangedalong the first direction.
 17. A method according to claim 15, whereinthe mask includes a rectangular opening having its length directionalong the first direction.
 18. An orifice plate manufactured by themethod according to one of claims 15 to
 17. 19. An ink-jet printerhaving a nozzle hole and/or ink groove manufactured by the methodaccording to one of claims 15 to
 17. 20. An illuminating apparatus forforming a linear illumination area on a surface to be illuminated, saidapparatus comprising:an anamorphic optical system for bringing anillumination beam into focus with respect to a first direction and forbringing the illumination beam into focus with respect to a seconddirection substantially perpendicular to the first direction,sequentially; and an imaging optical system for forming a linearillumination area extended in the first direction on the surface bybringing the illumination beam focused sequentially with respect to thetwo directions into focus with respect to the second direction and intodefocus with respect to the first direction on the surface.
 21. Anilluminating apparatus for forming a linear illumination area on asurface to be illuminated, said apparatus comprising:an anamorphicoptical system for bringing an illumination beam into focus with respectto a first direction and for bringing the focused illumination beam intofocus with respect to a second direction substantially perpendicular tothe first direction, sequentially; an imaging optical system for forminga linear illumination area extended in the first direction on thesurface by bringing the illumination beam focused sequentially withrespect to the two directions into focus with respect to the seconddirection and into defocus with respect to the first direction on thesurface; and a beam splitter for forming a plurality of beams serving asthe illumination beam by splitting light from a light source, whereinsaid imaging optical system causes the plurality of beams to overlapeach other on the illuminated surface and brings each of the pluralityof beams into focus with respect to the second direction and to defocuswith respect to the first direction on the illuminated surface.
 22. Adevice manufacturing method comprising the steps of:bringing anillumination beam into focus with respect to a first direction and withrespect to a second direction substantially perpendicular to the firstdirection sequentially by an anamorphic optical system; and forming, byan imaging optical system, a linear illumination area extended in thefirst direction on a mask by bringing the illumination beam focusedsequentially with respect to the two directions into focus with respectto the second direction and into defocus with respect to the firstdirection on the mask; and exposing a workpiece through a pattern withinthe linear illumination area on the mask.
 23. An illuminating apparatusfor forming a linear illumination area on a surface to be illuminated,said apparatus comprising:an anamorphic optical system for bringing anillumination beam into focus with respect to a direction substantiallyperpendicular to a longitudinal direction of the linear illuminationarea; and an imaging optical system for forming the linear illuminationarea on the surface by bringing the illumination beam focused withrespect to said direction into focus with respect to said direction onthe surface and to defocus with respect to the longitudinal direction onthe surface.
 24. An illuminating apparatus for forming a linearillumination area on a surface to be illuminated, said apparatuscomprising:an anamorphic optical system for bringing an illuminationbeam into focus with respect to a direction substantially perpendicularto a longitudinal direction of the linear illumination area; an imagingoptical system for forming the linear illumination area on the surfaceby bringing the illumination beam focused with respect to said directioninto focus with respect to said direction; and a beam splitter forforming a plurality of beams serving as the illumination beam bysplitting light from a light source, wherein said imaging optical systemcauses the plurality of beams to overlap each other on the illuminatedsurface and brings each of the plurality of beams into focus withrespect to said direction and to defocus with respect to thelongitudinal direction on the illuminated surface.
 25. A devicemanufacturing method comprising the steps of:bringing an illuminationbeam into focus with respect to a direction by an anamorphic opticalsystem; and forming, by an imaging optical system, a linear illuminationarea on a mask by bringing the illumination beam focused with respect tosaid direction into focus with respect to said direction on the mask andto defocus with respect to the longitudinal direction on the mask.